JPS62274048A - Free-cutting steel - Google Patents

Abstract

PURPOSE:To prolong tool life and to improve dimensional accuracy by specifying the amounts of C, Si, Mn, Sn, Sb, As, and Fe so as to improve machinability. CONSTITUTION:This free-cutting steel has a composition consisting of, by weight, 0.05-0.5% C, <=0.5% Si, <=1.5% Mn, 0.01-1% Sn, and the balance Fe or further containing, besides the above, 0.01-1% Sb and/or 0.01-1% As. The above free-cutting steel is used as material for substitute parts for brass, etc., and, on application of this steel, machining can be carried out with high accuracy and tool life can be remarkably prolonged.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Purpose of the Invention (Industrial Field of Application) This invention relates to free-cutting steel with excellent machinability, such as watch parts, telephones, radios, etc. It has excellent machinability and is used as a material for parts for telecommunication equipment such as stereos and televisions, parts for precision machinery such as computers, automobile and bicycle parts such as various knobs, spoke nipples, and grease nipples, and other brass substitute parts. It concerns free-cutting steel.

(Prior Art) Conventionally, free-cutting steels used for the above-mentioned applications include sulfur and sulfur composite free-cutting steels, which are established as JIS SUMII~43, as well as p, s, and pb.
Free-cutting steel with composite additives (for example, Daido Steel Co., Ltd. standard: 5FC2F).

3F, 4F), and free-cutting steel with composite additions of S, Pb, and Te (for example, Daido Steel Co., Ltd. standard: 5FC3FT).

(Problems to be solved by the invention) Conventional free-cutting steels are used in a wide range of fields as mentioned above, and have excellent machinability, so they can significantly improve the life of cutting tools such as drills. It has the outstanding feature of being able to Depending on the intended use, shape, and required cost of the cutting part, a free-cutting steel having a composition other than those exemplified above may be desired.

(Purpose of the Invention) This invention was made in view of the above-mentioned conventional demands, and its purpose is to provide a free-cutting steel that has excellent machinability even with ingredients other than those known to date. It is.

[Structure of the invention] (Means for solving the problems) The free-cutting steel according to the present invention has a C: 0.05 to 0 in weight%.
．． 5%, Si: 0.5% or less, Mn: 1.5% or less, S
Contains n: 0.01 to 1.0%, Sb: 0 as necessary
．． 01-1.0%.

Contains one or two of As: 0.01 to 1.0%, and Bi and Ca as necessary.

It is characterized in that it contains one or more of Pb, S, Se, Te, and Tl (1) in a total amount of 0.01 to 0.5%, with the balance consisting of Fe and impurities.

Next, the reason for limiting the composition range (weight %) of the free-cutting steel with excellent machinability according to the present invention will be explained.

C: 0.05-0.5% C is an element necessary to ensure the mechanical strength of various parts such as watch parts, precision machinery parts, and telecommunication equipment parts. % or more. However, if it is contained in a large amount, hardness increases and machinability decreases, so the upper limit is set at 0.5%.

Si: 0.5% or less Si is an element that acts as a deoxidizing agent during steel melting, but if it is contained in a large amount, machinability is reduced, so the upper limit is set to 0.5%.

Mn: 1.5% or less Mn is an element that acts as a deoxidizing agent and desulfurizing agent during steel melting, but if it is present in large amounts, machinability (tf I'll do it.

Sn: 0.01-1.0% Sn is effective in improving the machinability of steel used as a material for various parts, extending the life of tools, and improving the surface finish of parts. In order to obtain such an effect, it is contained in an amount of 0.01% or more. However, if it is contained in large amounts, it will impair the hot workability of steel.
The upper limit is set at 1.0%.

Sb: 0.01-1.0% As: 0.01-1.0% sb and as are effective elements for further improving the machinability of steel by adding them in combination with Sn. ,
In order to obtain such effects, it is good to contain 0.01% or more of each of them, but if they are added in large amounts, they will impair the hot workability and toughness of the steel, so even if they are added, the upper limit should be 1.0% of each. It is best to set it to the following.

Bi, Ca, Pb, S, Se, Te, TJI: One or more types in total 0.01 to 0.5% Bi, Ca,
Pb, S, Se, Te, and TJI are all elements that are effective in improving the machinability of steel, and can be used as materials for various parts by adding them in combination with Sn, which is an element that improves machinability. This is effective in further improving the machinability of steel. However, since too much content impairs the manufacturability and toughness of steel, the total content of each of these elements is preferably in the range of 0.01 to 0.5%. When S is added as an element for improving machinability, the S content is added in the range of 0.2 to 0.4%, and when it is desired to improve hot workability, M n /
It is desirable to adjust the composition as necessary so that S is 3 or more, and when S is not contained, it is more desirable to keep the content as an impurity element to 0.015% or less.

In addition, in order to improve the machinability of steel, P is set to 0.0.
It may be added in a range of 4 to 0.09%, and it is desirable that the O content be in a range of 200 to 500 ppm, if necessary.

(Example) 50 kg of each steel having the composition shown in Table 1 was melted in an induction furnace, then ingot formed, and after blooming and product rolling, cutting test pieces were taken and cutting under the conditions shown in Table 2 was performed. In this cutting test, the cutting speed V = 50 m/m
The lifespan of the drill was investigated. The results are also shown in Table 1.

Table 2 As shown in Table 1, inventive steels No., 1, and 2, in which Sn was added alone to the basic component steel, all had a cutting speed of 50 m/min.
The tool life (drill life) at min is considerably increased compared to the comparison steel 22.

It is clear that the steel of the present invention has extremely excellent machinability. In addition, the machinability of steels 3 to 5 of the present invention, in which 11a or more of Sb and As were added in addition to Sn, was further improved;
, the machinability is further improved in steels of the present invention Nos. 6 to 8 in which one or more of Se, Te, and Tu are added in combination,
One or more of Sb, As and Di, Ca, Pb, S, Se
, Te.

It is clear that the stiffness of steel according to the present invention, No. 9, in which one or more types of TJI were added in combination, was considerably improved. Furthermore, the steel of the present invention has a suitable amount of P added thereto.

Invention steel No. 1 with appropriately adjusted 12 and 0 contents
It was confirmed that improvement in machinability can also be achieved satisfactorily in Nos. 3 and 14.

[Effect of the invention 1 As explained above, the free-cutting steel according to the present invention has, in weight percent, C: 0.05 to 0.5%, Si: 0.5% or less, Mn: 1.5% or less. , Sn: 0.01-1.0%, Sb20, 01-1.0%, As: 0 as necessary
．． 01 to 1.0%, and also contains Bi, Ca, Pb, S, Se, Te, if necessary.
, one or more of Tl in total from 0.01 to
Since it contains 0.5% and the balance consists of Fe and impurities, it has extremely excellent machinability, and the free-cutting steel of this invention can be used for watch parts, telephones, radios, stereos, televisions, and other electrical appliances. Parts for communication equipment, parts for precision machinery such as computers.

When used as materials for automobile and bicycle parts such as various knobs, spoke nipples, grease nipples, and other brass substitute parts, these cutting processes can be performed efficiently and with high precision, making it possible to cut carbide molds and high-speed tools. It is possible to significantly extend the life of tools such as molds, and it has the significant effect of improving dimensional accuracy, reducing tool costs, and reducing tool replacement rigidity. It will be done.

Claims (7)

[Claims] (1) In weight%, C: 0.05-0.5%, Si: 0.
5% or less, Mn: 1.5% or less, Sn: 0.01-1.
A free-cutting steel characterized by containing 0% Fe and the balance consisting of Fe and impurities. (2) In weight%, C: 0.05-0.5%, Si: 0.
5% or less, Mn: 1.5% or less, Sn: 0.01-1.
0%, and Sb: 0.01-1.0%, As: 0.0
Contains one or two of 1 to 1.0%, the balance being Fe
Free-cutting steel characterized by consisting of and impurities. (3) In weight%, C: 0.05-0.5%, Si: 0.
5% or less, Mn: 1.5% or less, Sn: 0.01-1.
0%, and Bi, Ca, Pb, S, Se, Te, Tl
A total of 0.01 to 0.5 of one or more of the following
%, with the balance consisting of Fe and impurities. (4) In weight%, C: 0.05-0.5%, Si: 0.
5% or less, Mn: 1.5% or less, Sn: 0.01-1.
0%, and Sb: 0.01-1.0%, As: 0.0
One or two of 1 to 1.0%, and further Bi, C
One or two of a, Pb, S, Se, Te, Tl
A free-cutting steel characterized by containing a total of 0.01 to 0.5% of carbon dioxide and more, with the balance consisting of Fe and impurities. (5) Claim (3) or (4) in which the S content is 0.2 to 0.4% and the Mn/S is 3 or more.
Free-cutting steel as described in section. (6) The free-cutting steel according to any one of claims (1) to (5), containing 0.04 to 0.09% P in the balance Fe. (7) The free-cutting steel according to any one of claims (1) to (6), wherein O: 200 to 500 ppm in impurities.